Refining lead alloys and alloys containing lead, tin, copper, or antimony.



y 4 iiiiii'jj iggzy F, A. STIEF.

REFINING LEAD ALLOYS AND ALLOYS CONTAINING LEAD, HN,COPPER, 0R ANTIMONY.

APPUCATION FlLiD MAY 6. I915- 1,283,427. Patented Oct. 29, 1918.

2 SHEETS-SHEET -F. A. STIEF.

marmmc LEAD MLOYS AND ALLOYS CONTAINING LEAD, TIN, coma, on ANTIMONY.

APPLI FILED MAYG I9! 5. 1,283,427. Patented Oct. 29,1918.

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is performed UNITED STATES PATENT OFFICE.

FRED A. STIEF, OF EAST ST. LOUIS, ILLINOIS.

REFINING LEAD ALLOYS AND ALLOYS CONTAINING LEAD, TIN, COPPER, OR ANTIMONY.

Specification of Letters Patent.

Patented Oct. 29, 191 8.

Application filed Kay 6, 1915. Serial No. 26,207.

To all whom it may concern:

Be it known that I, FRED A. STmr, a citizen of the United States and a resident of the city of East St. Louis, county of St. Clair, and State of Illinois, have invented a new and useful Improvement in Refini Lead Alloys and Alloys Containin Lea. Tin, Copper, or Antimony, of whic the following is a specification.

his invention relates particularly to processcs for removing arsenic from mixtures containing tin, antimony, lead and arsenic No claim is made herein for the apparatus. The invention consists in exposing the molten mixture of metals to the action of iron, limestone or lime in, a furnace, and separating the arsenic from the mixturein the form of speiss, which is composed largely of arsenic and iron or calcium in the form of an arsenid or an arsenate. The operation in a furnace of special design, wherein the metal is exposed to the action of the heat but protected from the action of the furnace gases, and which furnace may be equipped with a se arator for" se arating the s elss from the uid metal.

urther detais of the" invention appear hereinafter, reference being had to the details of construction and operation of the furnace shown in the accompanying drawings for pur ose of illustration. What is claimed ,as t e invention is de ned in the appended claims. llhthe drawings, in which the same reference characters referto like partsin the several views,

Figure 1 is a horizontal section through the furnace on the line 1--1 in Fig. 2, showing the hearth in plan;

Fig. 2 is a vertical longitudinal section of the furnace on the line 22 in Fig. 1; and

Figs. 3 and bare vertical transverse sections of the.furnace on the lines 3-3 and 4- 1 in Fig. 2, respectively.

The furnace shown inthe drawings comprises vertical side walls 10 inclosing a rectangular. hearth 11 which is divided into three long narrow sections by means, of longitudinal partition walls 12. The fire box 13 is at one endof the hearth and the chimney 14 is at the other end. The hearth and fire box are covered by tiles 15 which are sup ortcd on the side walls 10, partition wals 12 and front wall 16 of the furnace. The tiles are fitted with rings or loops 17 in their tops, by means of which they can be readily removed to give access to trade or well 25.

the hearth. At each end of the hearth is a low cross wall 18 which retains the fluid metal on the hearth. The hot gases of the furnace pass over the cross walls 18 and above the hearth between the longitudinal walls 12, and a large part of the heat of the furnace gases is absolved by these Walls and by the roof tiles.

At one end of the hearth is an inlet or charging duct 19 which leads through the side wall of the furnace from the hopper or trough 20 on the outside of the furnace. Molten metal may be run through this charging duct on to the hearth. The partltion walls 12 are each provided at one end the hearth to the next.

At the opposite corner of the hearth from the inlet or charging duct is an outlet duct 22 which is provided with a spout 23 at the level of the hearth. In the bottom of the hearth near the outlet end is an orifice 24 beneath which is arrangcdan iron recep- This well 25 constitutes a settling chamber for separating the fluid metal and the'speiss, and it may be surrounded by a water jacket 26 through which cooling water is caused to circulate by means of the pipes 27. At the bottom of the settling chamber 25 is a discharge duct 28 and tap hole 29.

Preferably the hearth is sloped from the charging duct slightly downward toward the outlet duct so that there will be a uniform fall for the molten metal throughout its course. This fall should not be too steep as it is desirable that the metal should take one-half hour or more to flow from the inlet to the outlet duct in a wide thin stream of one-half inch or so in depth.

The process may be operated with any suitable flux for removing the arsenic but a mixture of about one-half scrap iron and one-half charcoal or coke is preferable. The scrap iron and carbon are charged on to the hearth from above and are spread uniformly along its entire length. The metal to be refined is charged on to the hearth in a molten state, and as it flows slowly along the hearth it is filtered through the scrap iron and brought into intimate contact therewith. The charcoal or coke covers the molten metal and protects it from the furnace gases. The iron combines with the arsenic in the molten metal and forms speiss, which is a fluid of li ter specific gravity than the molten metzfi along with the metal to the outlet duct. lhe metal and speiss together float into the settling chamber, where the metal sinks to the bottom. When the settling chamber is full the speiss will flow out of the furnace through the outlet duct 22. The metal can be ta ped ofi' either continuously or at intervals from the bottom of the settling chamber then b the discharge duct 28 and tap hole 29. Ihe carbon and iron can be renewed from time to time as is required. The temperature of the furnace should be such as to maintain the metal and speiss at a red heat. The metal in the bottom of the separation chamber should be cooled to a temperature at which any speiss commingled therewith would solidify and float to the Tn case a flux containing limestone or lime is used the'arsenic and the calcium combine to form an arsenate which is not a fluid and which must be raked out of the furnace at intervals, This may be readily done by removing the tiles rom over the hearth without interfering with the continuity of operation of the process. When lime or limestone is used in the flux either alone or in combination with other substances a suflicient amount of calcium-carbonate and calcium-arsenate may be left in the furnace as a cover for protecting the metal from the furnace gases.

Among the advan of thisv process and apparatus are the f owing: The length of the path which themetal is caused to travel in its course over the hearth causes it'to be thoroughly commingled with the flux which it passes, and the thinness of the layer treat ed insures that all parts of the metal are subjected to the same treatment. The partitions absorb a large part of the furnace heat and conduct it to the metal, and they also retain the flux on the hearth and keep it spread out uniformly. The process may be worked continuously and the flux may be renewed as required without requiring the furnace to be cooled off or cleaned out, the metal may be charged in continuously, and the metal and speiss may be tap ed ofl continuously or intermittently as e'sired. The hearth iscomparatively short and compact, the partitions support the roof and enable loose tiles to be used in place of a solid arch, and the loose tiles afiord easy access to the hearth.

The settling chamber may be dispensed The speiss floats .with and instead the mixture of metal and speiss tapped off and cast in pigslfwhich are later remelted at alow heat to separate the metal from the speiss which has a higher melting point than the metal.

he invention is not restricted to the use of the Ingredients and proportions above described.

I claim the following as my invention:

1. process for refining alloys of lead, t1n, copper, or antimony, containing arsenic which comprises treatin the metal in .a thin layer at a red heat in t e presence of iron and separating out the speiss from the molten metal.

2. A process for refining alloys of lead, tin, copper, or antimony, containing arsenic which comprises treating the metal In a thin layer at a red heat in the resen-ce of iron and calcium compound an separating out the speiss from the molten metal.

3. A process for refining alloys of lead, tin, copper, or antimony, containing arsenic which comprises treating the metal in a thin layer at a red heat in the presence of iron and separating out the speiss from the mol ten metal by cooling the mixture in a settling chamber.

4. A process for refining alloys of lead, tin, copper, or antimony, containing arsenic which comprises treatin the metal in a thin layer at a red heat in t e presence of iron and separating out the speiss from the molten metal by cooling the mixture in a settling chamber and removing the speiss from the to 5. A process for refining alloys of lead, tin, copper, or antimony, containin arsenic which comprises treatin' the metal in a thin layer at a red heat in presence of iron and separatin out the speiss fromthe molten metal by.

6. A process {for refining ,81 f tin, copper, or antimony, which comprises treatin themetalma layer at a red heat in 51o presence ofj-ron and carbon and separating out the. speiss from the molten metal.

7'. A process for refining alloys of lead, tin, copper, or antimony, containing arsenic which comprises treatin the metal in a thin layer at a red heat in t e presence of iron,

on and separatmolten metal.

for continuously refining alloys of lead, tin, co per, or antimony, containing arsenic: whic comprises treating the metal in a thin layer at a red heat in the presence of iron and carbon in a furnace, renewing the iron and carbon from time to time and separating out the speiss from the molten metal by gravity.

10. The improvement in the process of refining alloys of lead, tin, copper, or antimony containin arsenic which comprises heating the meta in a thin layer in the presence of iron while maintaining a suitable material on top of the metal to prevent volatilization.

11. A process for refining alloys of lead,

tin, copper, or antimony containing arsenic which comprises heating the metal in a thin moving stream in the presence of iron while maintaining a sufiicient amount of calcium compound to form a flux on top of the metal to prevent volatilization.

12. A process for refining alloys of lead, tin, copper, or antimony containing arsenic which com rises heating the metal in the presence 0 iron in a thin movin stream while maintaining a flux on top of t e metal to prevent volatihzation.

Signed at St. Louis, Missouri, this 3rd day of May, 1915.

FRED A. STIEF. 

